Solar Cells for Space Applications - Gamma Radiation Resistance Testing for Polar Orbit CubeSats

This paper summarizes the results of electric properties measurement of degradation of solar cells for space applications due to gamma radiation. Two types of solar cells from companies AZUR SPACE Solar Power GmbH and SPECTROLAB, Inc. were tested. The solar cells samples were exposed to the different doses of 60Co gamma radiation source under +30/-30 �C temperatures placed in a special experimental box. The gamma radiation doses were increased as follows: 0, 0.5, 1, 2, 10 and 30 kGy. The I-V characteristics, open circuit voltage, maximum electric power, etc. were studied after every irradiation in the illumination-measurement chamber. Two primary aims of this study are as follows: 1. to investigate the changes in electrical properties under various gamma radiation doses and 2. to ascertain the temperature effect of low and higher temperatures to the proper function of the solar cells. In cooperation of Research Center Rez Ltd. (Department of Diagnostics and Qualification) with the Slovak company RMC, s. r. o. , the unique results of solar cell degradation were obtained in the conditions of space application, i. e. combination of gamma radiation and elevated/low temperatures simulating space environment conditions.